1. Field of the Invention
The invention relates to a semiconductor manufacturing technology. More particularly, the invention relates to a transistor structure and a method for fabricating the same.
2. Description of Related Art
In an integrated circuit of a semiconductor, field effect transistors are main components. The integrated circuit includes a great number of transistors, and performance and size of the transistors affect the overall performance and size of the integrated circuit.
A conventional field effect transistor having a silicon substrate as a base has a metal-oxide-semiconductor (MOS) structure, which includes a gate structure as well as a source region and a drain region on both sides of the gate structure and in the substrate. A channel region is between the source region and the drain region. In addition, the design of a thin film transistor may not need the silicon substrate as a base, but the channel region is still made of a silicon semiconductor.
According to research and development of semiconductor materials, the channel region of the field effect transistor may be replaced with an oxide semiconductor (OS), so that the transistor may be manufactured more easily. The performance of the channel region of the transistor made of the OS may depend on the quality of the oxide semiconductor layer.
Improving the quality of the channel region of the oxide semiconductor layer may allow the improvement of the quality of the transistor made of the OS.